Bukharest: Romanian prosecutors said on Monday they have charged Prime Minister Victor Ponta as part of a corruption probe, piling more pressure on the embattled politician to resign.

Ponta was charged with fraud, tax evasion and money laundering dating back to 2007-2011, before he became prime minister in 2012, the DNA anti-corruption agency said, adding that some of his property has been seized pending the outcome of the case.

The announcement came shortly after the 42-year-old hobbled on crutches through a crowd of reporters into the DNA headquarters to face prosecutors over the graft probe that was opened against him in June.

Sources said that he had refused to answer prosecutors` questions.

The investigation had sparked calls for Ponta to resign.

But after returning to work on Thursday following a month-long stay in Turkey for a knee operation, Ponta said on Sunday he was stepping down as head of the Social Democrat party while he fought the corruption allegations, but said he would stay on as premier.

Prosecutors also suspect Ponta of conflict of interest during his time as premier. But that probe was stymied when parliament, where Ponta`s party has a comfortable majority, refused last month to lift his immunity from prosecution.

The centre-left prime minister`s legal troubles prompted a fresh crisis in the European Union`s second poorest nation, where President Klaus Iohannis and the opposition have called on Ponta to step down.

Ponta has strongly denied the allegations and has promised to cooperate fully with prosecutors.

The money laundering and tax evasion allegations relate to his activities as a lawyer.

Ponta is accused of receiving the equivalent of around 55,000 euros ($61,000) from Dan Sova, a political ally and member of parliament suspected by prosecutors of abuse of power but who also enjoys immunity.

This probe is the latest in a string of investigations by the DNA, an anti-corruption agency within Romania`s prosecutor`s office, that have cost several prominent Romanians their jobs in recent months.